A nonchemical adhesive inspired by a parasitic worm that mechanically anchors itself to living tissue is reported in Nature Communications this week. The adhesive could improve the performance of self-adhesive bandages as it forms a much stronger bond in wet conditions than chemical adhesives that are currently used.

Self-adhesive bandages stick poorly to wet skin because water severely undermines the adhesive chemicals they rely on. To overcome this, Jeffrey Karp and colleagues have developed an adhesive that consists of an array of thousands of microscopic needles made from a hydrogel that swells when it comes in contact with water. When a bandage coated with such needles is pressed against moist living tissue, the needles penetrate the surface and swell up, forming a physically interlocking bond with the tissue. The authors took inspiration for their adhesive from the way in which the endoparasitic worm, Pomphorhynchus laevis, anchors itself within the intestine of a host. It does this by piercing the wall of the intestine with its long, needle-like proboscis, and then using muscles at its base to expand the proboscis into a bulb.

The team report that the adhesive performed significantly better than conventional adhesive bandages when tested on various animal tissues. It also achieved more than 3 times greater adhesive strength than surgical staples used for fixing skin grafts. The authors suggest that by loading the microneedles with therapeutic drugs, they could in future enable localized drug delivery.